See http://w140.com/smb/DC508A_SM.pdf page 1-1.

The DC508A is a 1.3GHz frequency counter. The left-hand side is for high frequencies at 50 Ohms. There is an LED labeled "Input Out Of Range". It lights if the input is not of high enough frequency

Victor, Just to be sure, did you test the fuse F1437 or the voltage across C1437. Also did you test as far as possible the driver transistor Q1430? Q1430 is not in the HV box. I think B, E and C can

Sweet knowing that I looked up the service manual I defiantly need C632. Now I just need to see if i can dig one up some where.

Hi members, I have since many years a tek 454. Few years ago the trace stop to show. Since I have more spare time to dedicate to my small lab I would like to repair it. The first step was to repair

OK, then what I was looking for was a significantly larger ripple.  What happens, voltage wise, at the very beginning when you turn on power, and then after the trace starts to dim?  Is there a

177 - B059769 appears to be the newest iteration of that unit. The last running change made was to C630 which was changed at B054650 and higher. Everything from that SN on is the most up to date

Hello Harvey: Thank you for your suggestion. I had checked the ripple content of power supply: +30V: 20mV p-p; should be 3mV or less -30V: 8mV p-p; should be 3mV or less +200: 195, 1.5V p-p;

Hi members : I am being repair my 7104 for the display issue, distortion of waveform, I damage ( crack the ceramic base when reinstallation ) the horizontal output IC 155 0178 00. Anyone can help

I'm out of ideas for trying to fix a Tek 2755 (2754/494AP) spectrum analyzer so I thought I would as the group for some ideas... The symptoms are the all of the front panel LEDs are on and there's

The main unit serial number is B108698 the serial number of the 177 is B059769

Hello All, Given that the Dallas DS1742W-120 is no longer available (excluding Chinese fakes), does anyone make an adapter board to use a more modern chip like the DS1744? I noticed that Glitch

Yep, I'm still around. I'll be at rickreall tomorrow for the hamfest. And I didn't forget that today is Valentine's day so my wife will be ok with whatever I haul home tomorrow 😁

Michael, Mine is defiantly the new style. The cap I am having trouble with is the user adjustable one on the front of the case. It does not have the 2 screws It has the panel mount nut. I will look

Looking at the schematic in my copy of the manual, I see that there is Text Box indicating "LOOPING COMPENSATION" with an arrow pointing above and to the right at C632. C630 is a smaller trimmer cap

Now I am honestly not sure. This is the looping cap that is actually in the test fixture 177 the curve tracer is a 577. From looking at the older documentation there are at least 2 versions of this.

Have you (and can you) safely measure the high voltage when this wandering happens?  First, though, I'd check ripple and voltage on the supplies.  That you have no stable trigger tends to make me

I just digged out the A3 HV board and checked all the transistors, diodes except CR247, CR298, which is a 10kV, 5mA silicon diode and a 800V, 25mA silicon diode, respectively. I forgot to check the

Actually every panel owns all the necessary LEDs, you can even see them blinking through the panel at power on :) The difference is that for the TV panel there is more labelling ("Line" trigger...),

IIRC there are also front panel differences that go with the TV trigger option, there's an extra button and some labelling differences.